How do you find AB if A=((-3, -7, -9), (2, -4, -1), (4, 2, -1)) and B=((-9, -1, 3), (3, -7, 3), (4, 9, -9))?

1 Answer
Yonas Yohannes
Feb 19, 2016

C=(( -30,-29,51), (-34,17,3 ), (-36,-4,12 ))

Explanation:

Multiply the rows of A by the columns of B for each entry of the new matric C: c_(ij) =sum_(k=1)^3 a_(ik)b_(kj)
c_11 = a_11b_11 + a_12b_21+a_13b_31 = 18-21-36=-39
expanding as above we get:
C=(( -30,-29,51), (-34,17,3 ), (-36,-4,12 ))

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